A product manager's skill set can make or break a product.
A product manager's skill set can make or break a product.
If you're a bad programmer and produce nothing, it'll (usually) quickly be discovered (though not always) even if you're good at talking. It's also easy to spot check in the interview before you hire them.
If you're a bad PM, but good at talking - it's easier to pass the interview and it can be harder to know they're bad and fire them.
Great PMs support their teams and make things better for the engineers they work with (especially by avoiding people working on stuff that doesn't matter). Bad ones make their teams miserable and add negative value. The role can also vary depending on the company (sometimes it includes product design work and sometimes it doesn't).
The best PMs I know are also really good at debugging/troubleshooting and have a technical background (I think necessary to be really great).
If you're long enough in the tech industry you've seen such people and learned to identify them with good certainty after one or two meetings.